Wikipedia:What is named after what

In move discussions, a common argument in discussing whether there is a primary topic and if so, what it might be, is that one topic is named after another.

Which is, unfortunately and quite simply, irrelevant.

Variations
Sometimes, it's asserted that a topic is primary because all other topics are named after it.

Other times, it's just asserted that a topic is not primary because it's named after another topic of the same name.

And there are some subtle combinations of these two basic errors. None of them valid.

The policy
The consensus is clear but not very well codified into policy!

primary topic makes no mention at all of considering what is named after what. (Perhaps it should.)

Closing discussions reads in part The closer is there to judge the consensus of the community, after discarding irrelevant arguments: those that flatly contradict established policy, those based on personal opinion only, those that are logically fallacious, and those that show no understanding of the matter of issue. (But note that this is just an information page.)

WP:ROUGH CONSENSUS reads in part Consensus is not determined by counting heads, but by looking at strength of argument, and underlying policy (if any). (But that's a guideline on deletion.)

Irrelevant but not unrelated
At the risk of seeming to split hairs, what is named after what is not unrelated to the question of primary topic. It can be very a helpful indication of where to look for evidence. But it is not evidence on its own.

If all other things by the same name are named after one of them, that's a good indication that it has long-term significance. But the question still must be asked, how much significance? If these other topics have grown in significance since their naming, they may be still more significant. Boston in America is far more significant than Boston, Lincolnshire.

Similarly, the thing after which the others were named was there before they were, or at least before they were known by that name. It was once the primary topic by usage. But is it now?

In each case we need to fall back on the explicit criteria. What was named after what can help our inquiries, but they cannot stop there.

Examples
''Please add to these lists. But please do not supply diffs, that unfairly singles out editors who may have made a mistake and risks bringing unproductive discussion here (or even to the talk page where it belongs). The curious can find the quote easily enough.''

Invalid arguments

 * ...the cattle etc. are named after the county...

The reality

 * Boston is named after Boston, Lincolnshire, but the American city is still the primary topic.